具有抗氧化活性茶多糖TPS- Ⅱ的分离纯化及其性质研究

从六安炒青绿茶水提物中分离纯化得到具有抗氧化作用的茶多糖组分TPS-II,经电泳和FPLC 方法检测TPS-II 为均一组分;其总糖85.3%、糖醛酸28.0%、蛋白2.8%,分子量为1.01 × 105D;气相色谱法分析得知其单糖组成为L- 鼠李糖、L- 岩藻糖、L- 阿拉伯糖、D- 木糖、D- 甘露糖、D- 葡萄糖、D- 半乳糖,摩尔比为2.98:1.58:4.27:1.00:1.82:2.25:6.98;红外光谱分析显示TPS-II 呈现多糖吸收特征峰,β- 消去反应推断TPS-II 中多糖与蛋白的连接为非O- 型糖肽键。     

蜜环菌多糖Am -Ⅰ的部分理化性质及结构研究

液体培养的蜜环菌水溶性胞外粗多糖经纯化得Am-Ⅰ,再经Sephadex G-200柱层析和醋酸纤维薄膜电泳鉴定Am-Ⅰ为均一性组分。采用凝胶色谱法得Am-Ⅰ相对分子量约为6.65×105Dal,旋光法得[α]D25为+100°,苯酚-硫酸法、Folin-酚法、Dische反应法测其糖含量、蛋白质含量和糖醛酸含量分别为91.51%、4.78%和2.81%。气相色谱分析表明:Am-I的单糖组成为D-葡萄糖、D-岩藻糖、D-阿拉伯糖、D-甘露糖、D-鼠李糖、D半乳糖、摩尔比为:17.05:0.33:0.36:1:0.42:13.67。红外光谱、纸色谱、Smith降解分析表明:Am-I是一种含半乳糖醛酸的酸性多糖,其结构主要由吡喃型单糖通过β(1→4)键和β(1→6)键连接而成。β-消去反应表明这种糖蛋白是非O-型糖肽键。     

杨桃多糖的提取研究

对杨桃采用水煮乙醇沉淀法粗提,复合酶法去蛋白,凝胶过滤柱层析进一步纯化后,得到杨桃多糖,通过紫外、红外扫描进行纯度和结构鉴定及分子量测定.结果表明,提取纯化的杨桃多糖是均一组分,纯度高,平均分子量为4.373×104,并且含有吡喃多糖、木聚糖、半乳糖、阿拉伯糖、葡萄糖、鼠李糖和果糖等单糖.     

海带中褐藻糖胶分级纯化及结构分析

为了纯化海带褐藻糖胶及研究褐藻糖胶结构,利用DEAE-Sepharose Fast Flow离子交换柱分离海带褐藻糖胶粗品,得到LP-1、LP-2、LP-3和LP-4 4个组分,通过Sephadex G-150凝胶柱对硫酸根含量较高组分LP-2、LP-3和LP-4进行进一步分离纯化及分子量测定,最终LP-2获得两种均一多糖LP-21和LP-22,其分子量分别为123和105 k Da,LP-3和LP-4为均一多糖,分子量分别为74和32 k Da。通过高效液相色谱法分析得率较高的组分(LP-21、LP-22和LP-3)单糖组成,用红外色谱法分析其结构。高效液相色谱结果表明,分级纯化后的组分(LP-21、LP-22和LP-3)主要由L-岩藻糖、D-半乳糖组成,还有少量D-葡萄糖、D-甘露糖、D-氨基葡萄糖、L-鼠李糖、D-木糖和D-葡萄糖醛酸。红外光谱分析表明,LP-21和LP-22的硫酸根主要结合在岩藻糖C_4位,LP-3硫酸根主要结合在岩藻糖C_2或C_3位上。     

菱叶红景天多糖的提取、纯化鉴定及理化特性研究

以有效的热溶水提法，从菱叶红景天植物中得到粗多糖RHP。RHP经乙醇分级得三个级分RHP-I，RHP-II，RHP-III，取RHPIII脱蛋白，脱色，DEAD-纤维素柱层析，Saphadex G-200柱层析分离纯化，色谱鉴定及初步理化特性分析，得一纯度较高的均一多糖RHPS。PC分析其单糖组成有L-阿拉伯糖、L-鼠李糖、D-葡萄糖和另一个待确定的组分组成。     

无花果多糖的部分理化性质研究

对无花果渣中的无花果多糖进行分离纯化,对其理化性质、得率、含量、分子量分布和单糖组成进行了分析。无花果多糖为灰色粉末,易溶于水,难溶于有机溶剂。碘-碘化钾反应阴性,为非淀粉多糖;得率为4.1%,总糖含量91%。紫外扫描表明不含蛋白质和核酸,红外光谱显示主要为吡喃多糖,分子量在5.92×105~1.95×106之间,主要由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖组成,其摩尔比值为1.93∶3.86∶0.46∶0.55∶7.42∶2.87。     

动态高压微射流技术对可溶性大豆多糖结构的影响

研究动态高压微射流技术(DHPM)处理对可溶性大豆多糖(SSPS)组分、相对分子质量、外观形态及单糖组成的影响。结果表明：经DEAE-Cellulose 离子交换从大豆粗糖中纯化得到SSPS-1 和SSPS-2 两个组分,高效凝胶渗透色谱(HPGPC)分析表明SSPS-1为含少量蛋白的杂多糖,SSPS-2为高结合蛋白含量的单一多糖;SSPS-1经DHPM处理后,相对分子质量由7.33 × 105 减少至5.11 × 105;电镜扫描观察其形貌由针状排列结构变成末端膨大呈球形的“火柴棒”状有序排列结构;气相色谱分析单糖组成表明：SSPS-1 主链中单糖L- 鼠李糖和D- 半乳糖醛酸的含量分别降低9.4%、17.1%,侧链部分的单糖L- 阿拉伯糖、D- 半乳糖、D- 岩藻糖、 甘露糖分别降低14.3%、26.3%、41.7%、60%,而D- 木糖、D- 葡萄糖、葡萄糖醛酸未检出。     

草菇多糖VVP-1b的分离纯化及其光谱分析

从草菇子实体中提取水溶性粗多糖,经脱蛋白、脱色、DEAE-Sepharose F.F和Superdex-200柱层析,分离纯化得到一种水溶性草菇多糖组分VVP-1b。采用液相色谱、紫外光谱、红外光谱等光谱方法对其部分理化性质和结构进行测定。结果表明:VVP-1b为均一组分,具有明显的多糖特征峰,含有β-吡喃糖苷键;其总糖含量、蛋白含量、糖醛酸含量分别为88.7%、7.8%、27.6%,相对分子质量为5.84×105;单糖组成及摩尔比为阿拉伯糖∶甘露糖∶半乳糖∶葡萄糖=4.0∶1.0∶1.4∶35.4。因此VVP-1b是一种均一的具有β-吡喃糖苷键的酸性多糖。     

香菇菌丝体多糖的化学结构与抗氧化活性分析

对香菇菌丝体多糖(Lentinus edodes mycelium polysaccharides,LMPS)的2种组分(LMPS-1和LMPS-2)进行化学结构特征分析,旨为香菇菌丝体多糖的构效关系研究提供依据。文中利用高效液相色谱法(HPLC)、气相色谱(GC)、红外光谱(IR)分析等对其化学结构特征进行解析,并测定其抗氧化活性。构成糖分析结果显示:LMPS-1单糖组成为阿拉伯糖、木糖、甘露糖和葡萄糖,其摩尔比为2.5∶0.8∶1∶1.8;LMPS-2的单糖组成为鼠李糖、木糖和葡萄糖,其摩尔比为4.2∶1∶2.7。LMPS-1和LMPS-2均有较强的抗氧化活性,LMPS-2更为显著。香菇菌丝体多糖主要由阿拉伯糖和鼠李糖组成的吡喃型多糖,有较强的抗氧化活性。     

珊瑚菌多糖RBP-Ⅰ的结构及抗氧化活性分析

珊瑚菌经热水浸提分离得到粗多糖,纯化后得到珊瑚菌多糖RBP-Ⅰ,采用凝胶渗透色谱测定其分子量,并结合Sephadex G-100层析柱鉴定其纯度。利用苯酚-硫酸法测定糖含量,碘-碘化钾法判定是否含有淀粉,考马斯亮蓝G-250法测蛋白含量,硫酸-咔唑法测糖醛酸含量。采用红外光谱扫描、气相色谱分析其结构及单糖组成。结果表明,RBP-Ⅰ的Mw为15857 Da,为均一多糖;总糖含量86.94%,糖醛酸含量5.14%,不含蛋白及淀粉;多糖RBP-Ⅰ中单糖的摩尔比为鼠李糖∶岩藻糖∶阿拉伯糖∶甘露糖∶葡萄糖∶半乳糖=1.00∶6.53∶1.99∶8.29∶70.05∶53.80;红外光谱表明其具有多糖特征峰,且为吡喃型多糖。体外抗氧化结果表明:当多糖质量浓度为10000μg/m L时,FRAP值达到0.0672 mmol/L,DPPH自由基的清除率达到22.83%,ABTS+·的清除率达到15.71%。由此可见,珊瑚菌多糖RBP-Ⅰ具有一定的抗氧化活性。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status